In Dr. Mario Theissen's paper that BMW published about their F1 engines several years ago, he clearly states his surprise at how much he misunderstood the torsional requirements of the engine at first. He thought the chassis would want an ultra- stiff engine, but he quickly learned that was not the case. I don't recall that he ever stated exactly why the chassis wanted a more compliant block, so I wanted to poll the audience.
Does anyone know why? And is it possible that the return of tunnels and compensating suspension geometry would benefit from a different stiffness?